Climatological and oceanographic data point to the global impact anthropogenic greenhouse gas emissions have on geochemical, atmospheric and ecological systems. Even a conservative interpretation of the data suggest dire consequences if current rates of CO2 emissions continue.
Here are some other reasons:
Or, the bottom line: $$$ and the opportunity to participate in the coming hydrogen economy. Perhaps we will soon be seeing the start of a "garage-biotech" revolution. Think about it - you don't need FDA approval to make gas from bugs.